Figure 8.
r2 and r2* relaxivity plots. In the panels A and C transverse relaxation rate R2, in the panels B and D the spin-spin relaxation rate R2* are each plotted against the respective iron concentrations. The data of panels A and B were acquired at 1.5 T, the data of panels C and D show the corresponding data acquired at 3 T, both on clinical MRI systems. In each panel, the left graphs show the data for Ad and RDB cells, the right graphs the data for VSV and McA cells, the top graphs show the datasets for PEI-Mag particles and the bottom graphs for SO-Mag particles. Free MNPs are plotted in black, cell internalized MNPs in red, and free complexes in blue and cell internalized complexes in purple.